Engine Blocks, Cylinders and Top End Kits
Easy Life Markets sells engine blocks and cylinder parts for small engines, with each item listed by bore size and engine type so you can match it to your motor. In this category you will find the parts that form the cylinder itself: complete cylinder kits, cylinder barrels and big bore top end kits. On car engines the block is one large casting. On many motorcycles and scooters the cylinder is a separate barrel that bolts to the crankcase, and that is what our current range covers.
What should you buy? If the bore in your engine is scored, worn oval or past its wear limit, a new cylinder is usually quicker and cheaper than reboring the old one. Choose a kit that matches your engine model and bore size, and check that it includes the piston and gaskets you need. Our current range includes two kits, described below, and we plan to add more.
What Is in This Category Today
This sub-category is part of our engine section in the wider auto parts department. The range is small for now, so here is exactly what it holds:
- The SDH150 cylinder kit (SDH150-A, B and C) with a 57.3mm cylinder sleeve, piston, piston rings and cylinder gasket set.
- The Yamaha PW50 60cc big bore kit for 1981 to 2009 models, with cylinder, head, piston, gaskets and studs.
Both are complete top end kits. That means you get the cylinder and the parts that work inside it, so you can rebuild the top of the engine in one job. If you only need a piston and rings for a cylinder that is still in good shape, see our pistons sub-category instead.
The rest of this guide covers engine blocks and cylinders in general, so it will help you choose the right part as more items arrive.
What an Engine Block Does
The block is the main structure of the engine. It holds the cylinders, where the pistons move. It carries the crankshaft in its main bearings at the bottom. It has passages for oil and, on liquid-cooled engines, for coolant. The cylinder head bolts to the top, and the oil pan or crankcase closes the bottom. The Wikipedia article on the engine block gives a useful overview of how blocks are designed and made.
On most car engines the cylinders are cast into one block, sometimes with pressed-in liners. On many motorcycle, scooter and small engines the cylinder is a separate part. It sits on top of the crankcase and is held down by studs. That design makes top end repairs much easier, because you can lift the cylinder off and replace it on its own.
Car engine blocks
Car blocks are large castings in cast iron or aluminium alloy. They come as bare blocks, short blocks with the crank, rods and pistons fitted, or long blocks with the head as well. Replacing one is a major job, normally done by a workshop with lifting gear and the right service data.
Motorcycle and scooter cylinders
Small engine cylinders are usually aluminium with an iron sleeve or a hard coating on the bore. Air-cooled cylinders have fins to shed heat. Liquid-cooled ones have water jackets. These are the parts in our current range, and they are a common home rebuild job.
Signs Your Cylinder or Block Needs Attention
Most cylinder problems show up as poor sealing, which affects compression, power and oil use.
- Scoring or deep scratches on the bore wall, often after a seizure or dirt getting past the air filter.
- Low compression that stays low even after new rings.
- Blue smoke and oil use on a four-stroke, caused by a worn or glazed bore.
- Visible wear where the coating or sleeve surface has worn through.
- Cracks in fins, stud bosses or water jackets, from overheating or over-tightening.
- Coolant in the oil or oil in the coolant on liquid-cooled engines, which can mean a crack or a failed head gasket.
Before you buy a new cylinder, measure the bore in several places with a bore gauge or have a workshop do it. If the wear is within limits, a hone and new rings may be enough.
Types of Cylinder Parts and Engine Blocks
There are a few ways to fix a worn bore. Each suits a different situation.
Complete cylinder kits
A cylinder kit includes a new cylinder, matching piston, rings, pin, clips and gaskets. Everything is sized to work together, so there is no machining needed. This is the most common choice for scooters and small motorcycles. The SDH150 kit is this type.
Big bore kits
A big bore kit replaces the standard cylinder with one that has a larger bore, plus a larger piston to match. That raises the engine capacity, as with the PW50 kit that takes the engine to 60cc. Big bore kits often need carburettor jetting changes. They may also affect whether the vehicle meets the rules for its intended use, so check that before you fit one.
Rebored cylinders and oversize pistons
Some cylinders can be bored out by a machine shop and fitted with an oversize piston. This works on iron sleeves and many car blocks. Coated aluminium bores usually cannot be rebored in the same way and are replaced or re-plated instead.
Sleeves and liners
Some engines use replaceable sleeves pressed into the block. A workshop can remove a worn sleeve and fit a new one. This is common on larger engines and some older designs.
Short blocks and long blocks
For cars, a short block or long block replaces most of the engine at once. These are large, heavy items. We will list them with full fitment detail if we add them to the range.
Engine Blocks and Cylinder Options Compared
| Option | What you get | Best for | Machining needed |
|---|---|---|---|
| Cylinder kit | Cylinder, piston, rings, pin, clips, gaskets | Worn or scored small engine bores | None |
| Big bore kit | Larger cylinder and piston, often head and gaskets | More capacity on small engines | None, but jetting may change |
| Rebore and oversize piston | Your cylinder, bored to suit a new piston | Iron bores and many car blocks | Machine shop work |
| New sleeve | A replacement liner fitted into the block | Sleeved engines | Workshop press and finish |
| Short or long block | Block with internal parts, plus head on a long block | Major car engine damage | None, but a big fitting job |
How to Choose the Right Cylinder or Block
Matching is everything with engine blocks and cylinders. A cylinder that looks right but differs by a few millimetres will not work. Use these checks.
- Identify the engine. Read the engine type or code stamped on the crankcase or block. Engine families like the GY6 and SDH series come in several sizes.
- Check the bore size. Compare your current bore with the diameter on our product page, such as 57.3mm on the SDH150 kit.
- Check the stud pattern and spacing. The cylinder must fit over the studs on your crankcase. Compare the photos and the hole spacing.
- Check the cooling type. Air-cooled and liquid-cooled cylinders are not interchangeable.
- Check the cam chain tunnel. On four-strokes, the opening for the cam chain must match your engine.
- Check the kit contents. Does it include the head, the piston, the gaskets and the studs? Read the list on the product page.
- Think about the rest of the engine. A big bore kit may need a matching carburettor setup to run well.
Not sure? Send your engine details and measurements through our contact page and we will help you check fitment before you order.
Fitting a New Cylinder: Tips and Safety
Fitting a cylinder kit on a small engine is a job many owners do at home. It takes care and patience. On car engines, block work is a job for a qualified workshop.
- Use the service manual. Head nut torque, tightening order and clearances come from the manual for your engine. Do not guess them.
- Clean all mating faces. Old gasket material on the crankcase or head will cause leaks. Scrape gently so you do not gouge the aluminium.
- Protect the crankcase. Stuff a clean cloth around the rod so nothing falls inside.
- Fit new gaskets. Base and head gaskets are single use. Our gaskets section has full sets for some engines, such as the Yamaha YZ125 full gasket kit.
- Oil the bore and piston. A light coat of clean engine oil protects the parts on first start.
- Guide the rings in carefully. Compress each ring as the cylinder slides down, so none catch or break.
- Check timing after assembly. On four-strokes, set the cam timing marks correctly before you start the engine.
- Break it in gently. Vary the speed and avoid long full-throttle runs at first.
Parts to Check While the Cylinder Is Off
A cylinder job gives you access to several other parts. Check them now to avoid opening the engine twice.
Crankshaft and connecting rod
Check for play at the big end and side to side movement. Our crankshafts sub-category includes the GY6 50cc crankshaft and an off-road motorcycle crankshaft assembly.
Cam chain and tensioner
A stretched cam chain causes noise and timing drift. The motorcycle timing chain repair kit is one example from our timing section.
Camshaft and rockers
Look at the cam lobes and rocker faces for wear. See our camshafts, including the CG125 camshaft set.
Pistons only
If the bore measures within limits, you may only need a piston. Examples include the GY6 125cc piston kit and the 64mm motorcycle piston kit.
Materials and Bore Surfaces
What a cylinder is made of affects how it wears, how it is repaired and how much heat it can handle. It is worth knowing which type you have before you shop for engine blocks or cylinder parts.
Cast iron
Cast iron is heavy but very hard wearing. Many older car engine blocks are iron, and iron bores can usually be rebored several times with oversize pistons. Iron holds heat longer, so it warms up more slowly.
Aluminium with an iron sleeve
This is a common mix on scooters, small motorcycles and many modern cars. The aluminium body is light and sheds heat well. The iron sleeve gives a hard running surface for the rings. Sleeved bores can often be rebored, or the sleeve replaced by a workshop.
Aluminium with a plated coating
Many performance motorcycles and some cars use a thin hard coating on the bore instead of a sleeve. It is light and wears well, but it cannot be bored oversize in the usual way. A damaged plated bore is usually replaced or sent for re-plating.
How to Measure a Bore
Measuring tells you whether you need a new cylinder or just new rings. It takes a few minutes with the right tools.
- Clean the bore so there is no oil film or carbon at the top edge.
- Measure the diameter with a bore gauge or inside micrometer at the top, middle and bottom of the ring travel.
- Take each reading twice, once front to back and once side to side. The difference shows whether the bore has worn oval.
- Compare the readings with the standard size and wear limit in your service manual.
- Check the surface by eye and fingertip for scoring, flaking or bare patches.
If you do not have a bore gauge, a local workshop can usually measure the cylinder quickly. Bring the cylinder clean and dry.
Air-Cooled and Liquid-Cooled Cylinders
Air-cooled cylinders rely on fins and air flow, sometimes helped by a fan shroud on scooters. They are simple and light. Keep the fins clean and the shroud in place, or the cylinder will run hot.
Liquid-cooled cylinders have water jackets and are fed by a pump and radiator. They hold a more even temperature, which helps with power and wear. When you replace one, refill and bleed the cooling system properly so no air is trapped. Parts for the cooling side sit in our cooling section.
The two types are never interchangeable, even on engines from the same family. Always match the cylinder to your engine's cooling type.
Looking After Your Cylinder
A new cylinder lasts much longer when the engine gets good care.
- Keep the air filter clean and sealed. Dust wears bores quickly.
- Use the oil type and change interval in your owner's manual. On two-strokes, mix fuel at the correct ratio.
- Fix lean running and air leaks quickly. They make the engine run hot.
- Keep cooling fins clean on air-cooled engines, and keep coolant topped up on liquid-cooled ones.
- Warm the engine up before working it hard.
Who These Parts Suit
Our cylinder kits suit scooter and small motorcycle owners, youth bike families, small repair shops and anyone bringing a project engine back to life. They are a practical way to rebuild a worn top end without machine shop costs.
If you work on cars, keep an eye on this section. We plan to add engine blocks and larger cylinder parts with full part numbers and fitment notes, so you can match them the same way. Until then, our team can tell you what is coming if you send your engine code.
The current price and availability are shown on each product page. If a part does not suit your engine, our return and refund policy explains what to do. For delivery details, see our shipping policy.
Frequently Asked Questions
What is the difference between an engine block and a cylinder?
The block is the main body of the engine. On many small engines the cylinder is a separate part bolted to the crankcase. On most cars the cylinders are part of the block.
Do your engine blocks fit cars?
Our current range is for small engines. We plan to add more, so contact us with your engine code if you need a car part.
Should I buy a cylinder kit or just a piston?
If the bore is scored or worn past its limit, buy a cylinder kit. If it measures within limits, a piston and rings may be enough.
Does a big bore kit need tuning?
Often, yes. The larger capacity usually needs carburettor jetting changes so the engine does not run lean.
Can I fit a cylinder kit at home?
On small engines many owners do, with basic tools, a torque wrench and the service manual. On car engines, use a qualified workshop.
Are gaskets included?
Both of our current kits include gaskets. Check the contents list on each product page for the exact parts.
Where can I find more help?
Our FAQ page answers common ordering questions.